Hee hee. Yeah, I was so surprised he turned out to be a rabid Trumpite. 
Sounds like a great idea.
What’s the downside?
Fuck it. I mean that very literally.
She bought the certificate, so My Pillow already has the money.
What I would do: spend the certificate on a pillow, something where you don’t have to spend anything more than the value of the certificate. Don’t unwrap it. Save it, and give it to her next Christmas, along with a copy of Michelle Obama’s book “for bedtime reading”.
Great idea! And add Comey’s book on truth and justice to Obama’s.
Mary Trump’s book about the horrible family is pretty readable as well.
I wouldn’t try to escalate the political bickering inside your immediate family, because feuds only anchor you more intensely to the thing or person that you dislike.
If there is any reason to continue cooperating with your sister, for example kids, elder care, or joint family property, then bite your tongue and seek therapy to save your sanity. It may have a side benefit of annoying her that she can’t get a rise out of you. I call this “taking the high road for a low-road reason”.
Yes, donate the pillow to a shelter or similar. They probably need all the pillows they can get.
I don’t know much about them, but apparently there are companies that will buy your gift cards from you. Here’s the first link I found. CardCash I just Googled “sell your gift cards”.
I would just throw it in the recycling bin.
Assuming the OP’s sister is just doing it to make a political statement, the more of a spectacle he/she makes regarding the gift, the more satisfied the sister will be that she caused a reaction. Particularly if she can boast of it to her conservative friends.
The worst thing for her would be for the OP to do or say nothing. If she asks about it, just casually remark that you already had a pillow and probably lost or recycled the gift certificate.
Or you could take out the stuffing, cut out some eye holes and ship it back to her as a Klan hood.
I like this. May I steal it for my own low road reasons?
And love your user name!
Personally I would give or resell it to someone who might buy his products of their own volition, giving him additional revenue.
My favorite hot dog was Nathan’s. I even named a dachshund Nathan. Then I found out the chief executive is a Trump supporter and has held a fundraiser for him. Sadly, I haven’t eaten those hotdogs since Chump became president.
I think we have a Winner.
He doesn’t have views that differ from mine, he actively attempted to persuade the President to invoke martial law and mobilize the military to stop the President-elect from being seated.
Prior to that Friday meeting, he was just a douchebag Trumpie, now he belongs in Leavenworth.
This was my first thought but, sadly (for the OP), there’s no places interested in buying a MyPillow gift card that I could find. Still, I’d consider selling it on eBay or Craigslist or similar and buying something you actually want and have no moral objections to.
Somewhere out there is some guy who’s ready to give MyPillow $50 or whatever amount the card is for. If you buy a pillow and do whatever with it, that guy is going to also spend $50. But if you sell that guy your card for $35, then MyPillow doesn’t get any extra money and you have $35. At that point, go buy yourself a Christmas present you’d have wanted or donate the cash or whatever. Donating it just to taunt your sister though doesn’t sound that far removed from giving a MyPillow gift card to taunt someone.
Hopefully the resale market will become flooded with them so there’s no reason for anyone to buy more. Someone should start a list of the certifiably insane Trumpists: Sidney Powell, Marjorie Taylor Greene, now Lindell …
In case you hadn’t decided what to get your sister next Christmas:
I’d politely hand it back to her with a “no thanks”. Be the better person.
Hilariously, he’s not looking to start a pillow company, he’s looking for a ‘unionized American Pillow Company’ he can use to buy and brand his own pillows.
I can hardly wait for his $300 pillows made with American union labor.
I’d hand it back to her and say, “I see that you think that christmas is a time for spreading spite and hatred, which is sad. You and I will no longer be exchanging gifts, as I don’t wish to tempt you to be that way any further. If you are able to be nice, we can continue to speak to each other. I’ll be sad if we can’t. Goodbye for now.”
My family relationships are good, but predicated on a long history of delicately avoiding certain topics - a practice I encourage by utterly cutting off contact with people who can’t respect the terms of the peace (until they rectify the problem, anyway). I’ve done it before, on at least two occasions, and I would certainly do it again.